On Jun 24, 2008, at 9:01 PM, Boris Zbarsky wrote:
>
> Francois Remy wrote:
>> And there's no CSS or HTML specification that query to the browsers
>> to have some progressive rendering.
>
> Perhaps not, but there is also no specification that requires
> browser to not have:
>
> * { display: none ! important }
>
> in their default user stylesheet.
>
> The fact is, progressive rendering is something users want: they
> want to start reading the start of a long document before it's all
> loaded.
I think we might be mixing up two different senses of "progressive
rendering":
1) Rendering a document where the content has only partially loaded
(some of the document markup or external content references like
images), but all stylesheets have loaded so style is correct for the
part that is rendered.
2) Rendering a document when there are still pending external
stylesheet loads, so that content may render with incorrect style.
Users clearly want Type 1 Progressive Rendering and most browsers do
it. But Type 2 is generally considered an undesirable artifact (Flash
Of Unstyled Content) and usually only considered an acceptable
tradeoff when waiting for style is likely to be slow (for example on
mobile devices).
The sense of "progressive rendering" in the CSS Variables discussion
is all about Type 2, since that is the only case affected by
references to variables defined in other stylesheets which have not
yet loaded. Though, as I explained, this isn't really significantly
different from cascading with rules in other stylesheets that are not
yet loaded, as far as Type 2 progressive rendering is concerned.
Regards,
Maciej